This invention relates generally to latches, and more particularly to a latch for releasably securing one body portion, such as a hood, to another body portion, such as a cowl, of a truck-tractor.
Heretofore, truck- or semi-tractor hoods have been secured to the cowl or fender of the tractor by any of a variety of latches. In one type of latch, a spring-loaded piston is movable inside a metal cylindric member mounted on one body portion of the truck-tractor, the piston being movable outwardly with respect to the cylindric member against the bias of a spring. A metal hook member is connected to a metal U-shaped structure or yoke extending outwardly from the piston, the hook member being pivotable with respect to the yoke to hook or latch onto a hook on the other body portion and pull the piston outwardly with respect to the cylindric member, thereby securing the hook and cowl together. However, this type of latch is expensive to manufacture and assemble because of the complexity of the design and the close tolerances required for the moving parts. In addition, since the latch is constructed from metal, it may chip the painted surfaces of the truck-tractor in normal use.
Another type of latch comprises an elastomeric strap formed or molded with a lateral bore at one end for securing the end to one body portion of the truck-tractor and with a spherical or ball structure adjacent the other (free) end. The free end of the strap is pulled away from the secured end to stretch the strap until the spherical structure can be placed in a cup on the other body portion, thereby securing the two body portions together. Problems with this design include the difficulty of stretching the strap sufficiently to place the spherical structure in the cup and the tendency of the spherical structure to "pop" out of the cup, thereby releasing the latch.
Another example is an overcenter latch comprising an elastomeric strap having a lateral bore at one end and a pivotable metal plate or handle at the other end. One end of the plate may be placed in a hook member on, for example, the cowl by pivoting the plate on the strap. The other (free) end of the plate is then pressed toward the cowl until the strap is brought inwardly (toward the cowl) past the "hooked" end of the plate, thereby securing the hood to the cowl. The latch can only be released by pulling the free end of the plate away from the cowl, and the elastomeric strap tends to resist this since it is stretched by the plate as the plate is pulled from the cowl. While this overcenter latch is generally effective in securing the body portions together, it is relatively expensive and mechanical assembly of the plate and strap is required. In addition to increasing manufacturing cost, the metal plate will typically bounce against the painted surface of the cowl, for example, as the hood is being latched and released thereby chipping the paint from the cowl.